FreeCAD Mechanical Prototype Parts Modeling

I’m working on a small run of prototype mechanical parts and I’m looking for clean, parametric 3D models created directly in FreeCAD. The files will drive the next stage of the build, so the geometry has to be accurate, fully constrained, and easy for me to tweak later if dimensions shift during testing.

Here’s what I need from you:
• Native .FCStd files with an organized part tree and sketches fully constrained
• Any supporting STEP exports for quick sharing with vendors
• A brief note inside each file that explains key parameters or equations I’ll want to adjust

Everything will be used only for prototype development, so there’s no need to prepare production-ready drawings—just solid, watertight models that are ready for 3-axis machining or printing. If you already have a workflow in FreeCAD for mechanical parts and can turn around revisions quickly, let’s get started.

Metal carabiner, 2 parts. A modification of the modelo of the picture